Symptoms of anaphylaxis 

The time it takes for symptoms of anaphylaxis to develop depends on the cause.

If it was something you ate, such as peanuts, it can take anything from a few minutes to two hours. If it was something that entered your skin, such as a sting or an injection, it will usually take between five and 30 minutes.

Read more about the causes of anaphylaxis.

Allergic reactions can vary in severity. Sometimes they only involve mild itching or swelling, but in some people they can be severe and life-threatening.

Symptoms of anaphylaxis include:

  • itchy skin or a raised, red skin rash (hives)
  • swollen eyes, lips, hands and feet (angioedema)
  • feeling lightheaded or faint
  • narrowing of the airways which can cause wheezing and breathing difficulties
  • abdominal (tummy) pain, nausea and vomiting
  • collapse and unconsciousness

When to seek medical advice

If someone has the symptoms of anaphylaxis, they need urgent medical help, particularly if you know they have allergies.

You should immediately dial 999 for an ambulance.

Page last reviewed: 19/12/2012

Next review due: 19/12/2014